fix(assertions): throw error or warn when synth is called multiple times on mutated construct tree

packages/aws-cdk-lib/core/lib/stage.ts

@@ -141,11 +141,6 @@ export class Stage extends Construct {
    */
   public readonly parentStage?: Stage;
 
-  /**
-   * The cached assembly if it was already built
-   */
-  private assembly?: cxapi.CloudAssembly;
-
   /**
    * Validation plugins to run during synthesis. If any plugin reports any violation,
    * synthesis will be interrupted and the report displayed to the user.
@@ -210,14 +205,10 @@ export class Stage extends Construct {
    * calls will return the same assembly.
    */
   public synth(options: StageSynthesisOptions = { }): cxapi.CloudAssembly {
-    if (!this.assembly || options.force) {
-      this.assembly = synthesize(this, {
-        skipValidation: options.skipValidation,
-        validateOnSynthesis: options.validateOnSynthesis,
-      });
-    }
-
-    return this.assembly;
+    return synthesize(this, {
+      skipValidation: options.skipValidation,
+      validateOnSynthesis: options.validateOnSynthesis,
+    });
   }
 
   private createBuilder(outdir?: string) {

packages/aws-cdk-lib/core/test/synthesis.test.ts

@@ -6,6 +6,7 @@ import { Construct } from 'constructs';
 import * as cxschema from '../../cloud-assembly-schema';
 import * as cxapi from '../../cx-api';
 import * as cdk from '../lib';
+import { Template } from '../../assertions';
 import { synthesize } from '../lib/private/synthesis';
 
 function createModernApp() {
@@ -362,6 +363,26 @@ describe('synthesis', () => {
 
   });
 
+  test('can call synth multiple times without caching assembly', () => {
+    const app = new cdk.App();
+
+    const stages = [
+      {
+        stage: 'PROD',
+      },
+      {
+        stage: 'BETA',
+      },
+    ];
+
+    stages.forEach(({ stage }) => {
+      const stack = new cdk.Stack(app, `${stage}-Stack`, {});
+      // Assert that `Unable to find artifact with id` error is not thrown
+      expect(() => {
+        Template.fromStack(stack);
+      }).not.toThrow();
+    });
+  });
 });
 
 function list(outdir: string) {